The present invention relates generally to lock devices, particularly electronic lock devices such as electronic padlocks. Presently, many different types of electronic lock devices are used to secure doors, safes, vaults, and automobiles. Some of the more notable lock devices include those developed by the Mas-Hamilton Group, which are used primarily for safes and vaults. In particular, U.S. Pat. Nos. 5,170,431 and 5,893,283 disclose locks having electromechanical locking systems. Other devices, combining the electromechanical locking device with an electronic combination systems, are disclosed in U.S. Pat. Nos. 5,451,934, 5,488,350, and 5,488,660. Improvements on these lock devices include the addition of a self-contained power generation systems, as shown in U.S. Pat. No. 5,870,914, and power conservation systems, as shown in U.S. Pat. No. 5,896,026. Similarly, U.S. Pat. No. 5,617,082 discloses an electronic lock device having a single microprocessor, battery power, and keypad input.
Each of the previously cited lock devices are used in applications having unique characteristics that make the device operational for use with conventional electromechanical locking systems. For example, an automobile has a significantly large power source to power the lock. Similarly, a vault is often a large, heavy locking device that provides space for a large power source with substantial weight that dampens the effect of vibrations.
The power consumption required to operate electromechanical locks and the shock absorption characteristics often determine the size and the level of security afforded by the locking device. For example, a lock with a significant power source often provides a high level of security for a lock device due to its ability to manipulate heavier or multiple locking components. Additionally, a lock""s shock absorption characteristics allow the lock to remain secured when the lock is exposed to external tampering.
These characteristics have prevented the successful construction of an electronic lock that is sufficiently compact for use as a portable padlock while providing high levels of security. Reducing the size of the lock necessitates reducing the size of the power source used to operate the lock. Simply reducing the size of the power source contained in the lock, however, often results in unreliable operation of the lock due to the low power output provided by the power source such that the lock may be compromised by even a slight frictional resistance. On the other hand, constructing a lock having a sufficient level of security has, in the past, required significant power consumption and accordingly results in frequent power source replacements when a reduced size power source is used.
Moreover, locks that are conducive for use as a padlock require portability and reliability while providing sufficient strength and shock resistance necessary to withstand external forces that are quite different from safes and doors. A free hanging padlock is particularly vulnerable to shock loads from striking and other external forces such that the lock requires greater resistance to vibration. Additionally, power consumption for portable locks must also be minimized to allow the use of a light weight power source that provides sufficient usage life of the lock between power supply replacements.
Accordingly, there is a need for an electronic padlock that has a sufficiently reduced size to provide functionality and portability for everyday use. In particular, there is a need for a lock having an internal locking mechanism that sufficiently minimizes the power consumption requirements and provides proper lock operation with high level of security while allowing a sufficient battery life that is convenient to the user.
The lock construction of the present invention has a lock body defining an interior cavity and a shackle that is releasably received in the interior cavity. The shackle is movable to a locked position for securing to an object and an unlocked position for releasing the object between the shackle and the lock body. A locking mechanism is disposed within the interior cavity of the lock and comprises rotatable first and second members. The first member has a toothed section and is rotatable between a first position, to secure the shackle in the locked position, and a second position, to release the shackle for movement to the unlocked position. The second member includes a threaded section that is configured to intermesh and rotate with the toothed section of the first member. A motor is also included to rotate the second member and thereby the first member to respectively secure and release the shackle between the locked and unlocked positions.